Predicting tensile properties of monolayer white graphene involving edge effect

Abstract

Elastic properties of monolayer h-BN nanosheet, also known as white graphene, involving edge effect are systematically studied by the atomic finite element method. By carrying out a uniaxial tensile test along zigzag and armchair directions, respectively, the corresponding stress–strain curves of various types of h-BN nanosheets can be obtained by the first-order derivative of potential with respect to the strain. Consequently, zigzag and armchair Young’s moduli of h-BN nanosheets can be extracted from stress to strain curves in the small strain range which mainly follows a linear relationship. The results demonstrate that zigzag edge can always bear a slightly larger stress than armchair edge. As the size increases, both zigzag and armchair Young’s moduli decrease and get close to each other. This phenomenon indicates an isotropy material of h-BN nanosheets which is also verified by an analytical model. From a systemic study of various h-BN nanosheets, it is found that zigzag edge atoms have a distinctly increasing effect on elastic properties while armchair edge atom show a slight decreasing effect.